But the Frenchman, who pulled a goal back for the R's in the second half, says there is still belief that the Premier League's bottom side can repeat their feat of last season and beat the drop.
"We have to keep fighting, that is all we can do," said Cisse. "We did it last year, so why not this year again?"
Controversy erupted early in the second half at Loftus Road on Wednesday when QPR goalkeeper Rob Green fumbled the ball into his own net while apparently being fouled by West Brom's Marc-Antoine Fortune.
Cisse said: "I've seen the video again and again and it was clearly a foul for their second goal. He (Fortune) didn't attempt to play the ball.
"Rob couldn't do anything, it was a clear foul and it cost us dearly. We all feel sympathy for Rob, it wasn't his fault. There was nothing he could do, he was clearly fouled.
"Everyone in the stadium was waiting for the referee to award a foul. He didn't and it's cost us points."
Cisse produced a clinical finish to claim his fourth goal of the season but Rangers were denied a late penalty when Liam Ridgewell appeared to handle and finished with nothing to show for their efforts.
"It wasn't an easy finish," said Cisse. "I knew I didn't have much time but I had the option of chipping it or slotting it under the goalkeeper. It was a nice finish but we're all disappointed with the result.
"I didn't see the handball decision but it wasn't our day."